Firstly the guy who sells them "Ricks Mopars" appears to be Rick Ehrenberg and many years ago I remember the threads on Moparts on the issue of trying to get a decent advance curve from a Mallory was nearly impossible.
If you look at the exploded view of the Dizzy it shows what looks like the weights that comes with the original OEM Mopar distributers. The Early Mallory Dizzies that have the YL advance weights look like Mopar weights or at least the same. I like the look of the early Mallory Dizzies and have a few but the problem is I can usually only find them without the Vac Adv.
I've started to adapt a YL advance mech to a later style Mallory Housing but still need to finish the upper part of the unit. Its a bit of a mix and match scenario to be able to make it work as the heights change so that affects what button will work.
Then there's the availability of the springs for the Mopar/YL advance too.....